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Definition
| how populations of organisms change from generation to generation and how species originate |
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Definition
| patters of changes in groups of related species over broad periods of geologic time |
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| Lamarck's idea of use and disuse |
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Definition
| body parts of organisms can develop with increased usage, while unsued parts weaken |
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Definition
| some individuals possess alleles that generate traits that enable them to cope more successfully with their environment than other individuals. Those who produce more offspring are "fittest" |
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Definition
| eliminates individuals with extreme or unusual traits, most common trait is most adapted |
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Definition
| favors traits that are at one extreme of a range of traits-traits at opposite extreme are selected against; favored traits become more and more extreme through generations |
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Term
| Disruptive selection (diversifying selection) |
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Definition
| environment favors extreme or unusual traits, selecting against common traits |
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Term
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Definition
differential mating of males in a population-women increase quality of offspring by choosing superior males; males maximize quantity of offspring produced often leads to sexual dimorphism: differences in appearance of males and females |
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Term
| Sexual selection: male competition |
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Definition
| contests of strength that award mating opportunities to strongest males |
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Term
| Sexual selection: female choice |
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Definition
| leads to traits or behaviors in males that are attractive to females |
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Definition
| form of directional selection carried out by humans when they sow seeds or breed animals that possess desirable traits (dogs) |
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Term
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Definition
| provides raw material for new variation-invents new alleles that have never existed in the gene pool |
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Term
| Rearrangements or genetic recombination originate from what three events in the sexual reproductive process? |
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Definition
- crossing over between nonsister chromatids
- independent assortment (random combination of mom and dad chromosomes
- random joining of gamete during fertilization
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Term
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Definition
| the presence of two copies of each chromosome in a cell (can be stored for future generations in heterozygous condition) |
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Term
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Definition
| mating with unrelated partners-mixes alleles and creates new combinations |
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Term
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Definition
| the maintenance of different phenotypes in a popoulation (polymorphism is the coexistance of two or more phenotypes)...can be maintained by heterozygote advantage, hybrid vigor (heterosis), and frequency-dependent selection (minority advantage) |
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Term
| balanced polymorphism: heterozygote advantage |
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Definition
| heterozygous condition bears greater selective advantage than either homozygous condition; (sickle cell anemia) |
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Term
| balanced polymorphism: hybrid vigor (heterosis) |
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Definition
| superior quality of offspring from crosses between two different inbred strains of plants |
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Term
| balanced polymorphism: frequency-dependent selection (minority advantage) |
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Definition
| least common phenotypes have a selective advantage-common phenotypes are selected against, least common phenotypes become common and selective advantage is lost- alternate b/w low and high frequencies |
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Term
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Definition
| introduction or removal of alleles from the population when individuals leave or enter the population |
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Term
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Definition
| random increase or decrease of alleles; no reason but by chance |
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Term
| genetic drift: founder effect |
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Definition
| allele frequencies in a group of migrating individuals are by chance, not the same as their population of origin |
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Term
| genetic drift: bottleneck |
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Definition
| population undergoes dramatic decrease in size; small population becomes severely vulnerable to genetic drift |
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Term
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Definition
| individuals choose mates based on particular traits |
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Term
| nonrandom mating: inbreeding |
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Definition
| individuals mate with relatives |
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Term
| nonrandom mating: sexual selection |
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Definition
| females choose males based on attractive appearence, behavior, or ability to defeat other males in contest |
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Term
| Hardy-Weinberg genetic equilibrium can only occur when: |
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Definition
- All traits are selectively neutral (no natural selection)
- Mutations don't occur
- Population is isolated from other pop. (no gene flow)
- large population (no genetic drift)
- mating is random
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Term
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Definition
| popoultion divided by a geographic barrier |
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Term
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Definition
| formation of new species w/o presence of geographical barrier |
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Term
| sympatric speciation: polyploidy |
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Definition
| possession of more than the normal two sets of chromosomes found in diploid cells |
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Term
| sympatric speciation: balanced polymorphism |
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Definition
| ex. only insects w/ same color can associate and mate because the others die from not being camouflaged |
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Term
| sympatric speciation: hybridization |
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Definition
| two distinctly different forms of species mate and produce progeny along geographic boundary called hybrid zone |
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Term
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Definition
| relatively rapid evolution of many species from a single ancestor-ancestral cpecies introduced to are of diverse conditions available for colonization |
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Term
| Prezygotic isolation: habitat isolation |
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Definition
| species don't encounter one another |
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Term
| Prezygotic isolation: temporal isolation |
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Definition
| species mate or flower during different seasons or at different times of the day |
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Term
| Prezygotic isolation: behavioral isolation |
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Definition
| species doesn't recognize other species as a mating partner because it doesn't perform correct courtship rituals |
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Term
| Prezygotic isolation: mechanical isolation |
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Definition
| male and female genitalia are incompatible |
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Term
| Prezygotic isolation: gametic isolation |
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Definition
| male gametes don't survive in environment of female gamete or female gametes don't recognize male gametes |
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Term
| postzygotic isolation: hybrid inviability |
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Definition
| zygote fails to develop properly and aborts before reaching reproductive maturity |
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Term
| postzygotic isolation: hybrid sterility |
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Definition
| hybrids become functional adults, but are reproductively sterile (mule) |
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Term
| postzygotic isolation: hybrid breakdown |
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Definition
| hybrids produce offspring that have reduced viability or fertility |
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Term
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Definition
| two or more species that originate from common ancestor or become increasingly different over time |
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Term
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Definition
| two unrelated species sharing analogous traits because of similar biomes |
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Term
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Definition
| two related species or two related lineages that have made similar evolutionary changes after divergence from a common ancestor |
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Term
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Definition
| one species in response to new adaptations that appear in another species (happens b/w predator and prey) |
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Term
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Definition
| evolution occurs by the gradual accumulation of small changes |
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Term
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Definition
| evolutionary history consists of geologically long periods of stasis with little or no evolution, interupted or "punctuated" by geologically short periods of rapid evolution |
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